mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 78

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

Memory
If the FPVIOL flag is set in the FSTAT register, the user must clear the FPVIOL flag before starting another
command write sequence (see
4.4.6
4.4.6.1
If a command is active (FCCF = 0) when the MCU enters wait mode, the active command and any buffered
command will be completed.
4.4.6.2
If a command is active (FCCF = 0) when the MCU enters stop mode, the operation will be aborted and, if
the operation is program or erase, the flash array data being programmed or erased may be corrupted and
the FCCF and FACCERR flags will be set. If active, the high voltage circuitry to the flash array will
immediately be switched off when entering stop mode. Upon exit from stop mode, the FCBEF flag is set
and any buffered command will not be launched. The FACCERR flag must be cleared before starting a
command write sequence (see
4.4.6.3
In background debug mode, the FPROT register is writable without restrictions. If the MCU is unsecured,
then all flash commands listed in
and erase verify commands can be executed.
4.4.7
The flash module provides the necessary security information to the MCU. During each reset sequence,
the flash module determines the security state of the MCU as defined in
Reserved Memory
The contents of the flash security byte in the flash configuration field (see
changed directly by programming the flash security byte location when the MCU is unsecured and the
sector containing the flash security byte is unprotected. If the flash security byte is left in a secured state,
any reset will cause the MCU to initialize into a secure operating mode.
4-34
4. Writing an invalid command if the address written in the command write sequence was in a
protected area of the flash array.
Operating Modes
Security
WAIT Mode
Stop Mode
Background Debug Mode
As active commands are immediately aborted when the MCU enters stop
mode, it is strongly recommended that the user does not use the STOP
instruction during program or erase operations.
Active commands will continue when the MCU enters wait mode. Use of
the STOP instruction when SOPT1[WAITE] = 1 is acceptable.
Locations”.;ll;
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Section 4.4.2.5, “Flash Status Register
Section 4.4.3.2, “Command Write
Table 4-14
can be executed. If the MCU is secured, only the mass erase
NOTE
Sequence”).
(FSTAT)”).
Section 4.2.2, “Flash Module
Section
4.4.2.3) must be
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